Abstract: An oxygen delivery apparatus is used to supply oxygen-enriched air to a patient via a diffuser. A communication module containing an in-line flowmeter and oxygen concentration sensor is provided to measure the flow rate and oxygen concentration of the oxygen-enriched supplied to the patient. The length of a therapy session is also measured. The measured information is stored and periodically transmitted via a communication module including an internal modem to a remote computer system. The remote computer system includes a program that manipulates and stores the data transmitted from the module. Analysis of the data reveals the operational status of the oxygen delivery apparatus and whether the patient is complying with a prescribed regimen of use. The communication modules for a number of users in a given geographic can be monitored for efficient servicing.